With the proliferation of wireless communication systems, compatible handheld communication devices are becoming more prevalent, as well as advanced. Whereas in the past such handheld communication devices were typically limited to either voice transmission (cell phones) or text transmission (pagers and PDAs), today's consumer often demands a multifunctional device capable of performing both types of transmissions, including even sending and receiving e-mail. Furthermore, these higher-performance devices can also be capable of sending and receiving other types of data including that which allows the viewing and use of Internet websites. These higher level functionalities necessarily require greater user interaction with the devices through included user interfaces (UIs) which may have originally been designed to accommodate making and receiving telephone calls and sending messages over a related Short Messaging Service (SMS). As might be expected, suppliers of such mobile communication devices and the related service providers are anxious to meet these customer requirements, but the demands of these more advanced functionalities have in many circumstances rendered the traditional user interfaces unsatisfactory, a situation that has caused designers to have to improve the UIs through which users input information and control these sophisticated operations.
Keyboards are used on many mobile devices, including Personal Digital Assistants (PDAs), telephones, and handheld wireless communication devices. The size of keyboards has been reduced over the years, as newer, smaller devices have become popular. Cell phones, for example, are now sized to fit in one's pocket or the palm of the hand. As the size of the devices has decreased, the more important it has become to utilize the entire keyboard surface as efficiently as possible.
Given the recent trend in keyboard miniaturization, the keypads of some reduced key keyboards may contain a fewer number of keys. As a result, the keys contained thereon may be assigned multiple alphanumeric characters. In such a case, mobile devices will often have a software routine or program which facilitates determining the desired key input. For example, if there are two characters on a particular key, depressing a key twice will affect the choosing of a particular character. Another methodology includes a disambiguation software, or predictive text routine, wherein after depressing a key having a plurality of characters associated therewith, a given character or combination of characters are displayed and the user can choose from among the character or combination of characters the desired input.
Additionally, in order to facilitate user control, many keyboards on mobile devices have an input device for navigation through the graphical user interface. Interfaces include such devices as trackballs and rotating wheels which can be used to effect movement of a cursor or pointer, or to scroll up, down and about a displayed page. These navigation devices often occupy a relatively large amount of space on the incorporating mobile device. Because the navigation device is frequently used and often requires fine control, a lower end size limitation will normally be observed by device designers. To accommodate such larger, more convenient navigation devices on the housing of the mobile device, the amount of space that is available for the keys of the keyboard is correspondingly reduced if the keyboard and navigational device are proximately located to one another.
Current solutions for cursor navigation and textual input require a substantial portion of the front face of a handheld electronic device to be dedicated to these input means while detracting from the space available for the display screen. Additionally, they require movement of a user's hand from the keypad to the navigational instrument to activate the navigational input means. Therefore, it is desirable to configure a handheld electronic device so that the space required for the input devices are minimized and user control regarding character input is improved.